CVE-2023-25173

containerd is an open source container runtime. A bug was found in
containerd prior to versions 1.6.18 and 1.5.18 where supplementary groups
are not set up properly inside a container. If an attacker has direct
access to a container and manipulates their supplementary group access,
they may be able to use supplementary group access to bypass primary group
restrictions in some cases, potentially gaining access to sensitive
information or gaining the ability to execute code in that container.
Downstream applications that use the containerd client library may be
affected as well. This bug has been fixed in containerd v1.6.18 and
v.1.5.18. Users should update to these versions and recreate containers to
resolve this issue. Users who rely on a downstream application that uses
containerd’s client library should check that application for a separate
advisory and instructions. As a workaround, ensure that the "USER $USERNAME" Dockerfile instruction is not used. Instead, set the container
entrypoint to a value similar to ENTRYPOINT ["su", "-", "user"] to allow
su to properly set up supplementary groups.